街道层峡形态对夏季室外气温及热舒适的影响

Effects of street canyon geometry on summer outdoor air temperature and thermal comfort

为了研究南京典型夏季气候条件下街区层峡形态与室外气温及热舒适度的关系,采用参数化方法衍生设计出16个具有不同层峡形态的中心商业区(CBD)街区模型,利用建筑环境气温预测工具(STEVE Tool)进行数值模拟,计算得到各街区不同位置的24h实际区域室外气温(θ_a),并基于θ_a采用RayMan模型计算各街区中不同位置的24h热舒适度(PET).通过比较分析各街区不同位置区域室外气温与热舒适度的分布特征,得到街区层峡几何形态对区域室外气温及热舒适度的影响规律.结果表明:街区层峡高宽比与天空视角系数(ΨSVF)对区域室外气温及室外热舒适度均起主要的影响作用,但对气温的影响在白天与夜间呈相反趋势,对室外热舒适度的影响趋势全天较一致.

The parametric approach was applied to develop 16 CBD urban scenarios with different geometrical parameters in order to analyze the interrelationship between street canyon geometry and outdoor air temperature and thermal comfort based on the typical summer weather condition of Nanjing.The STEVE tool was employed to simulate and generate the 24-hour local outdoor air temperatures in different locations of the 16 urban scenarios.The 24-hour outdoor air temperatures were used to calculate the 24-hour thermal comfort index（PET）in the corresponding locations by using RayMan model.The influencing rules of street canyon geometry on local outdoor air temperature and thermal comfort were obtained based on comparative analysis on the distributional characteristics of outdoor air temperature and PET in different locations of each urban scenario.Results indicate that both the canyon aspect ratio and sky view factor exert crucial impacts on local outdoor air temperature and thermal comfort.The effects on air temperature between daytime and nighttime are contrary while the effects on thermal comfort are in accordance through all day long.